Speaking at the launch of Virgin Atlantic’s new Boeing 787 service to the US, Branson hit out at the constraints on the airline at Heathrow.

He said: “If we want to do a new route [at Heathrow] we have to close another because there are no slots. That is unlike anywhere else in the world.

“We are completely slot constrained in Britain. If a new runway were built [at Heathrow] there would be all sorts of routes Virgin Atlantic would want to open.”

The carrier operates from Heathrow and Gatwick, but Branson made clear he favours Heathrow for expansion.

Asked if he thought the Davies Commission on airport capacity should recommend a new runway at Heathrow or Gatwick, Branson said: “Heathrow is where people want to fly from. Heathrow is where all businesses are set up.”

He said: “Britain has held itself back by not having a new runway.”

Branson suggested there was no guarantee the next government would follow any recommendations of the Davies Commission to expand capacity.

He said: “I’m afraid politicians are all a bit cowardly when it comes to taking tough decisions.”